[lakshya-dhariwal]

Fixes #4643

When a sync Anthropic stream raises during iteration (mid-stream event: error or a dropped connection), AnthropicStream.__next__ bumped the exception counter and re-raised without ending the span, so the failed call never reached the backend. The async path already ends the span with ERROR on the same exception; #4101 edited the sync except block and left the span open.

This mirrors the async branch in the sync one: on a non-StopIteration exception, set the span status to ERROR, end it, and mark instrumentation complete (guarded so a repeated raise can't end it twice).

Verification (anthropic 1.13.0, mock transport, no network):

• The reporter's repro now reports sync raised=APIStatusError finished_spans=1 status=['ERROR'] (was finished_spans=0), matching async.
• New tests/test_streaming_error.py covers both sync and async mid-stream failure; sync test fails without the fix, both pass with it.
• Package suite (minus test_completion.py, which needs the pre-1.0 anthropic API): 196 passed / 71 failed, identical counts with and without the change - the failures are pre-existing cassette/env mismatches.
• ruff check clean; new test file ruff-formatted.

Summary by CodeRabbit

• Bug Fixes

  • Streaming failures now correctly record an error status and finish tracing spans for synchronous and asynchronous Anthropic streams.
  • Anthropic API errors are reliably propagated after streaming failures.

• Tests

  • Added regression coverage for synchronous and asynchronous streaming error scenarios.

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• packages/opentelemetry-instrumentation-anthropic/tests/test_streaming_error.py

🚧 Files skipped from review as they are similar to previous changes: 1

• packages/opentelemetry-instrumentation-anthropic/tests/test_streaming_error.py

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📝 Walkthrough

Synchronous Anthropic streaming errors now record error status, end the span, and mark instrumentation complete before re-raising. Regression tests verify span completion for synchronous and asynchronous streaming errors.

Changes: Anthropic streaming errors

Layer / File(s)	Summary
Complete spans on stream errors packages/opentelemetry-instrumentation-anthropic/opentelemetry/instrumentation/anthropic/streaming.py, packages/opentelemetry-instrumentation-anthropic/tests/test_streaming_error.py	The synchronous exception path records error status, ends the span, and marks instrumentation complete before re-raising. Tests assert that synchronous and asynchronous stream errors raise anthropic.APIError and finish exactly one span with error status.

Priority: ➖ Normal

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix · Severity of issue fixed: Medium

Merge Risk: 🟡 Moderate · up to 75ee9

The new streaming regression tests may fail in a supported Anthropic 0.x environment with both HTTP packages installed. Match the test client to the SDK before merging.

Security architecture risk: 🔵 Low · up to 682c5

Synchronous streaming failures now complete their existing trace instead of leaving it open. The change introduces no new access or deployment boundary. Handling of provider-supplied error text still depends on the application’s tracing configuration.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

• inferred — The changed authority is limited to completion of the affected request’s existing span. Provider or transport failures can influence its error description, but the inspected delta adds no credential access, tenant-selection mechanism, network destination, or persistent-state mutation.

Trust Boundaries and Controls

• observed — Prompt and response content capture has dedicated controls, whereas the changed status-description assignment is not gated by the content-capture flag. Tracing uses the configured provider. Whether downstream processing redacts exception text, or policy requires it, remains unresolved; no concrete sensitive-data disclosure was established.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 5 functions across 2 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 4 passed

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly and concisely describes the main change: ending the span when a synchronous Anthropic stream fails during iteration.
Linked Issues check		Issue [#4643] requires failed synchronous Anthropic streams to end their span with ERROR and prevent later successful cleanup. AnthropicStream.__next__ now records the exception, sets `StatusCode.…
Out of Scope Changes check		The changes are limited to the synchronous Anthropic stream failure path and regression tests for synchronous and asynchronous stream errors. The httpx2 and httpx compatibility logic supports the …

Full details: Linked Issues check

Explanation

Issue [#4643] requires failed synchronous Anthropic streams to end their span with ERROR and prevent later successful cleanup. AnthropicStream.__next__ now records the exception, sets StatusCode.ERROR, ends the span, and sets _instrumentation_completed before re-raising. The guard prevents duplicate completion. The generic exception handler covers API error events and connection failures. The new synchronous regression test verifies one finished span with ERROR; the async test confirms matching behavior.

Full details: Out of Scope Changes check

Explanation

The changes are limited to the synchronous Anthropic stream failure path and regression tests for synchronous and asynchronous stream errors. The httpx2 and httpx compatibility logic supports the regression tests in the stated dependency environments. These changes directly support issue [#4643]. No unrelated implementation or test changes are shown.

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Actionable comments posted: 1

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Inline comments:
Review comments at
@packages/opentelemetry-instrumentation-anthropic/tests/test_streaming_error.py:
- Line 6: Update the streaming error test’s HTTP client import and dependency
compatibility so it uses httpx with Anthropic 0.x and httpx2 with Anthropic 1.x,
or narrow the test dependency range to Anthropic 1.x; preserve compatibility
with the versions declared in the test configuration.

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Reviewing files that changed from the base of the PR and between 8d9c93f and 682c55d.

📒 Files selected for processing: 2

• packages/opentelemetry-instrumentation-anthropic/opentelemetry/instrumentation/anthropic/streaming.py
• packages/opentelemetry-instrumentation-anthropic/tests/test_streaming_error.py

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[charan-rathore]

Checked this out locally and the fix itself holds. With anthropic 1.13.0, both tests pass, and with streaming.py reverted to main the sync one fails. A connection drop mid-stream (a ReadError after two events) also ends the span with ERROR on this branch. One problem with the test file: it imports httpx2, which is not in this package's uv.lock (anthropic 0.86.0, httpx 0.28.1). In that locked env test_streaming_error.py fails at collection with ModuleNotFoundError. If I install httpx2 on 0.86.0, both tests fail with 'Invalid http_client argument; Expected an instance of httpx.Client but got httpx2.Client'. With plain httpx they pass on 0.86.0 and fail on 1.13.0, which wants httpx2. The pyproject allows >=0.86.0, so the test needs to pick the client class that matches the installed anthropic, or pin the version it was written for.

[lakshya-dhariwal]

Good catch, thanks for checking it against the lockfile. The test now imports httpx2 when available and falls back to httpx, matching whichever one the installed anthropic depends on. Verified in both envs: anthropic 0.86.0 + httpx 0.28.1 (locked) and anthropic 1.13.0 + httpx2 - sync test fails on main and passes on this branch in both.

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